Air valve carburetor



`MEW l2, WEL L.. E. PERRINE LSGSSB.

AIR -VALVE CARBURETOR Filed April 16, 1928 gyn/vanto@ ffy??? @fari/fe Patented May `12, 1931 UNITED STATES PA'M .N '1T v'ol-Fica LESTER E. PERRINE, 0F DETRIT, MICHIGAN, ASBIGNOR TO GENERAL MOTORS RESEARCH CORPORATION, OF DETROIT, MICHIGAN, l.A CORPORATION: OF DELAWARE Am VALVE caminamos. v

Application led AApril 16,

This invention relates to carburetors of the air-valve type and it is an object of the invention to provide\certain new and useful improvements in carburetors of this type.

One of the problems encountered in the construction of a carburetor of the air-valve type is that of designing thecarburetor so that it will supply to the engine on which it is installed a combustible mixture contain ing the desired proportions of fuel and air at all speeds of the engine. This problem arises due to the well-known fact that if, what may be termed, a simple carburetor of the air valve type, is so constructed as to sup-A ply a combustible mixture containing the desired proportions of fuel and air at a given i engine speed and load it will supply too lean or too rich a mixture at other engine speeds and loads. It is, therefore, an object of this invention to provide a carburetor of the air-valve type so constructed that lit will supply a combustible mixture containing the desired proportions of fuel and air to the cylinders of the engine on which it is installed mdier all conditions of ,engine speed and More specifically, it is an object of this invention to provide a carburetor of the airvalve type provided with a poppet ty e of air-valveso controlled that the ratio o fuel to air in the combustible mixture supplied to the cylinders of an internal combustion enginey may be automatically varied at any predetermined rate as the speed and load of the engine changes. This objectA can be attained to some extent by substituting for the simple spring, which ordinarily controls the air-valve, a yspring so constructed, ora' series vof springs so arranged," that equal in- .crements of pressure applied to it or them will cause different deflections thereof. Either of these solutions is, however, more or less unsatisfactory and expensive due to the difficulty of obtaining a single spring with A the desired deflection characteristics and the diiculty of obtaining and arranging a series of springs to give desired dliection characteristics. I, therefore, lprefer to use the means hereinafter described and shown in 1228. Serial No. 270,341..

the accompanying drawings to effect the desired result. Q

In the drawings:

Figure 1 1s a side 'elevation of my carbui retor mstalled onan'internal combustion en- 55 gine. Y 4

Figure 2 is a longitudinal section through Athe carburetor taken on the line 2--2 -of Fi re 8.

` igure 3.a section on the line of Figure 2. Y

Referring to the drawings, the reference character 10 indicates an internal combustion engine which is provided with an intake manifold 11 having a riser 12 to which .65

The level of the fuel within the oat cham- Vber 1s maintained constant by the'iioat 18 through any suitable mechanism, such as that indlcated at 19. Above the float chamber is located an air conduit 20 which includes the riser 1.3 in which is located the throttle valve 21 which 1s adaptedto be operated by an arm i 22.A Within the conduit, adjacent the riser end, there is located a mixing venturi 23 into i which extends the jet- 24 which opens -at its opposite end into the ioat chamber belowthe 30 fuel level thereof.

Adjacent its end opposite the riser, there 1s provided in the upper wall of the conduit 20 an air inlet opening 25 which is controlled by a valve 26 provided with a stem 27, ex' 85 h the lower wall of the con- Y tending throu duit into the oat chamber. At a point'distant from the valvevstem 27 there is provided a bushing 28 which is threaded through the upper wall of the oat `chamber and on which 9 is threaded a lock-nut 29. Slidably mounted end with a circumferential iian' e 30 which 1s adapted to limit the upwar movementl thereof with respect to the bushin is a shaft e dash of 31 which may be operated from t the vehicle through any suitable mechanism. The lower end of the shaft 31' is hollow 1n the bushing 28 and provided at its lower A lower end,-a washer 34 seated on a pin 35. Surroundin the portion of the rod 33 between the ange 30 and the washer 34 is a coil spring 36 which bears at its opposite-ends against the flange and washer, urging the rod 33 downwardly. ,l

Secured to the upper wall of the float chamby theilanges 37 is a channel-shaped member 38, the up is shaped to provi er surface of whose web e a cam surface 39. Extending through the channel of the member 38 and fulcrumed on the cam surface 39 is a lever 40 through which and the vertical slots 41 in the flanges 37 extends a pin 42 which prevents movement of the lever lengthwise of the member 38. The lever 40 is pivoted at its opposite ends to the lower end of the rod 33 and the lower end of the valve stern 27 by the pins 43 and 44, respectively.

- In the float chamber directly below the valve stem 27 is provided a dash-pot 45 in which is located a piston 46 to which is securedan upwardly extending rod 47. To the upper end of the rod 47 and to lower end of the valve stein 27 is pivoted, by the pins 48 and 44, respectively, a link 49.

When the throttle valve 21 is opened and the engine cranked the pressure in the conduit 20 is reduced to sub-atmospheric by the suction of the engine. This reduction of pressure in the conduit causes the valve 26 to open against the pressure of the spring 36 and air to How into the conduit through the opening 25. The air flows through the conduit, a portionA of it passing into the venturi 23 and mixing therein with vthe fuel which has been discharged from the jet 24 due to the reduction of pressure in the conduit. This primary mixture then passes out of the venturi and mixes with the remainder of the air, forming a combustible mixture of the proper proportions which then manifold to the cylinders of the engine.

As has been intimated, if in, what has been termed, simple carburetors of the type described, the s ring which resists the movement of the air-valve is adjusted to give the proper fuel-air ratio at a given engine speed the mixture uwill become too rich or too lean at other speeds and loads.' In my carburetor,

, the fulcrum of the lever 40 shifts upon movement of the air-valve requiring an increasin ly greater increase in pressure to open the va ve a iven amount and, conversely, a decreasing y smaller decrease in pressure to allow the valve to close a given amount as the air valve opens or closes. It is now obvious that, with my arrangement, by a suitable selection of cam shape, the ratio of fuel to air in the combustible mixture supplied to the cylinders of the en 'ne may be automatically .varied at any pre etermined rate.

The dash-pot, as is obvious, serves to damp the movementi.` e.` prevent fluttering-of the air valve. The initial pressure on ,the

asses through the intake spring 36 may be varied b screwing the bushing 28 up or down and tisie bushing may be locked in any adjusted position by the lock-nut 29. The engine, it is obvious, may be choked by moving the shaft 31 downwardly.

Though I have described and illustrated a specific embodiment of my invention it is to be understood that my invention is not limited thereto but includes all modifications with the scope of the appended claims.

The expression varied at any predetermined rate, or expressions of like import, used in this specification and the appended claims is to be understood to cover the special case where the rate is zero, i. e. where there is no variation.

I claim: 1. In a carburetor, a passage through which air is adapted to flow to the cylinders of an internal combustion engine, a valve for controlling the flow of air through the passage, aspring for resisting the o ning of the valve, and means for transmitting the movement of the valve to the s ring including a lever having a varyinlgfu crum.

2. In a carburetor, a passage through which air is adapted to flow to the cylinders of an internal combustion engine, a valve for y flow of air through the passage, a spring Jfor resisting the opening of the valve, and means including a lever fulcrumed on a cam surface for transmitting the movement of the valve1to the spring.

3. In a carburetor, an air passage, a fuel nozzle projecting into the air passage, a valve for directly controlling the admission of air into the air passage and the flow of air past the fuel nozzle, and means adapted to oppose at a variable rate increasing resistance to the opening of the valve.

4. In a carburetor, an air passage, a fuel nozzle projecting into the air passage, a valve controlling the for directly controlling the admission of airA into the passage and the flow of air past the fuel nozzle, and means adapted to oppose at a predetermined variable rate increasing resistance to the opening of the valve.

5. In a carburetor, an air passage, nozzle projecting into the air passage, a valve for directly controlling the admission of air into the air passage and the flow of air past the nozzle, means including a spring device to oppose at a variable rate increasing resistance to the `opening of the valve, and means for varying the initial stress vonr the spring device.

6. In a carburetor, an air passage, a fuel nozzle projecting into the air passage, a valve for directly controlling the admission of air into the air passage and the How of air past the nozzle, means adapted to oppose at a. variable rate increasing resistance to the opening of the valve,.and means whereby the a fuel valve may be closed against the pressure of the air owin thereby.

7 In a car uretor, an air passage, a fuel nozzle projecting into the air passage, a valve for directly controllin the admission of air into the passage and t e flow of air past the nozzle, means adapted to oppose at a variable rate increasing resistance to the opening of the valve, and means for damping the movement of the valve.`

8. In a carburetor, an air passa e, au opening through which fuel is adapte to be discharged into the air passage, a valve for directly controlling the admission of air into the air passage and the flow of air past the opening, and means adapted to oppose at a continuously variable rateA increasing 4ret'sistance to the opening of thevalve.

9. In a carburetor, an air passa e, an opening through which'fuel is adapte to be discharged into the air passage, a valve for directly controlling the admission of air into the air passage and the flow of air pastthe opening, and means, includin a spring and means operatively interpose between the spring and the valve, adapted to oppose at a varia le rate increasing resistance to the opening of the valve.

In testimony Whereoi I ax m si nature.

LESTER E. PlayIt INE. 

